136 Miscellaneous Intelligence. 
mat continued firing with more than 74% of the largest seper a 
powder which it may have withstood, and no cast-iron gun with 
much as this. 
I have not the data necessary to determine accurately the velocity, 
and consequently the force, which this reduction of the charge 0 
powder must make in the "shot ; ; but if we take the force of the 
shot in the direct ratio of the weight of the charge of Bete we 
shall have 261, instead of 372°8, as representing the “number of 
pounds of shot raised one foot by each eos of metal in thé gun,” 
as these numbers are in the ratio of 70 t 
I am not able to state what has sonaetedeeh the greatest charge 
of powder borne by Armstrong’s gun of 12 tons, carrying a shot 
of 300 pounds; but, reducing the charge of 60 pounds, as given 
by me, in the ratio of 70 t 0 100, we have a charge of 42 instead 
_ of 60 pounds of powder, an 6 a consequent reduction of the force 
of the gun — « foot pounds ” to 273 “ foot pounds.” 
IT have thought it the ook ares to make this correction, “ 
in a ol tetas of the force of the Dahlgren & R 
iven in the same paper to which this is a correction, the quail 
of powder then understood by me from all that had been published 
by government Aa ines as constituting a service charge was ta- 
ken as one of the factors in assigning the measure of the force to 
5. Cretaceous Coal in New Mexi <n a letter from Prof. 
Joun LeConte, dated Fort Craig, New Mexico, Oct. 3d, 1867, be 
states that through the facilities afforded him by General W. 
Wright, Chief Engineer of the eastern division of the Uniots 
Pacific Railroad, he has been enabled to make an examina- 
us ae and are the same sao mentioned by Dr. New- 
pt. Ives’ Expedition) and arry (Re 3 
